1. Field of the Invention
The present invention relates to an alignment substrate, a liquid crystal display (LCD) panel including the alignment substrate, and a method of manufacturing the alignment substrate. More particularly, the present invention relates to an alignment substrate for preventing alignment errors even though a misalignment occurs between two substrates when the substrates are combined, an LCD panel including the alignment substrate, and a method of manufacturing the alignment substrate.
2. Discussion of the Background
An LCD panel includes a lower substrate having a pixel electrode, an upper substrate having a common electrode, and a liquid crystal layer interposed between the lower substrate and the upper substrate. When an electric field is between the pixel electrode and the common electrode, an arrangement of liquid crystal molecules of the liquid crystal layer changes. The optical transmittance of the liquid crystal molecules is controlled by the changed arrangement of the liquid crystal molecules to display an image.
A wide viewing angle is one important factor for improving display quality of the LCD panel. In order to broaden the viewing angle, a patterned vertical alignment (PVA) mode or a super patterned vertical alignment (SPVA) mode that divides a pixel into a plurality of domains has been developed. However, the PVA mode or the SPVA mode requires additional processes for forming a slit pattern or a protrusion pattern to form a multi-domain structure. Further, afterimages or spots may be generated around the slit pattern or the protrusion pattern, or transmittance may be reduced.
In order to form the multi-domain structure without the slit pattern or the protrusion pattern, a photoalignment method has been developed. For example, alignment layers are formed on an upper substrate and a lower substrate, respectively, and a pretilt angle of the alignment layer on the upper substrate is different from that of the alignment layer on the lower substrate. When the two substrates are combined, a final alignment direction is determined from a vector sum of alignment directions of the alignment layers formed on the upper substrate and the lower substrate, respectively.
However, if a misalignment occurs between two substrates when they are combined, the final alignment direction determined from the vector sum may erroneous.